The 2014 Campaign Ads That You Just Can't Stop ReplayingStates that could determine which party controls the Senate next year have been barraged for months with campaign ads. For better or for worse, here are some of the most noteworthy.

What is it that can make a certain cat video go crazy on the Internet? That mysterious quality, that certain je ne sais quoi — whatever it is — that's exactly what the candidates, including one Iowa Republican campaigning for Senate, have tried to harness this year.

If you're living in one of the few states that could determine which party controls the Senate next year, chances are you've been barraged for months with campaign ads — online, on air and in the mail. In the blur, some of these commercials — for better or worse — might still be ringing in your head. Here's a roundup of some of the best and worst campaign ads of 2014.

The first comes from Iowa Senate candidate Joni Ernst, who introduces herself in this ad saying, "I'm Joni Ernst. I grew up castrating hogs on an Iowa farm." She continues, "So when I get to Washington, I'll know how to cut pork." Cue the pig squeal:

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You want to stop thinking about it, talking about it, but you can't. That's gold in the campaign world. But does that make it the best ad of 2014? Erika Franklin Fowler of the Wesleyan Media Project says actual effectiveness is harder to nail down.

"It's actually a harder job than you might think to define the 'best' and the 'worst.' I think it's easier to define the ones that stick out," she says.

OK, so let's revisit the ads that stuck out for whatever reason — some of them simply by virtue of relentless repetition. Like this one from Tea Party Patriots, an outside group that blamed Democrat Mary Landrieu of Louisiana for the Affordable Care Act. In it, the narrator says "Mary Landrieu cast the deciding vote to make you live under Obamacare":

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Or wait. Maybe it was ...

"Kay Hagan cast the deciding vote to make you live under Obamacare."

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No, no, no. This is the guy to blame:

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"Mark Pryor cast the deciding vote to make you live under Obamacare."

And then there were the ads that were memorable for making a great splash, only to see the candidate drag in the polls later. Here's Terri Lynn Land, the Republican candidate for Senate in Michigan:

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In this ad she says, "Congressman Gary Peters and his buddies want you to believe I'm waging a war on women. Really? Think about that for a moment ... "

She takes a sip of coffee, and spends two-thirds of the commercial saying ... nothing. The idea was, how could a woman wage a war on women? But Democrats thought of a few answers for that and have been hammering her on her stance on pay equity and abortion rights ever since.

There were also negative ads. Media analysts tally more from Democrats than Republicans this year, the possible reason being it's harder to change people's minds about President Obama than it is to discredit a challenger. But some of these ads memorably backfired.

In Alaska, Democrat Mark Begich suggested his opponent Dan Sullivan let a dangerous felon loose when he was state attorney general. He says, "I was on the Anchorage police force for 20 years. ... He let a lot of sex offenders get off with life sentences. One of them got out of prison, is now charged with breaking into that apartment building, murdering a senior couple and sexually assaulting their 2-year-old granddaughter."

Problem was, it's unclear whether Sullivan ever handled the case, and the victims' family was so offended the campaign yanked the ad.

But there were some positive ads, too. Senate Minority Leader Mitch McConnell had Noelle Hunter tell this story of how her ex-husband kidnapped their daughter and ran off to Africa.

She says, "I reached out to Sen. McConnell, and he took up my cause personally. I can't even talk about him without getting emotional. He cares. He cared about me and my children, when other people didn't."

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The spot ran for a full minute (that's forever in TV time). But with the control of the Senate at stake, money no longer seems to be an object.